I have a 2004 Rubicon. I lost cylinder 1 about two weeks ago. I have been trying to do a little research on the engine's from the 97-00 and the 01-06. What is the difference if any between these to motors? I have a friend with a 99 he is willing to sell me. The reason I am curious is when I call the salvage yards the is a 6-800 dollar price difference between those model year engines and I want to know what the difference is and if I would be a easy swap or is it two entirely seperate motor configurations? Any tips or advice would be greatly appreciated
The bottom ends should be the same and interchangeable. The heads, FI and ignitions are different. You could take the older short block and swap on your top end. You'll need the newer cam, I would get new cam and bearings and use that.
the 97-99 4.0Ls have a normal distributor, no 2 Cat converters on the exhaust manifold, An older style less efficient intake manifold, and different computer settings and I believe they changed the valve timing and or the cam for 00-06. For 00-06 they changed to the rail distribution, put two cats on the exhaust manifold, changed the computer settings and made it more emissions "friendly". To compensate for power loss they put on a newer style intake manifold.